The temperature dependence of the H-1 NMR spectrum for the D2O-solubilized Aerosol-OT (AOT)-C6D6 system in the reversed micellar state has been investigated in the temperature range 323-353 K. From the H-1 chemical shift variation of the AOT polar segment protons and of the HDO proton, it has been assumed that a structural transition of water incorporated into the polar core occurs at 343 K and that this transition is the result of the variation in interaction between water molecules within the polar core and those solubilized at or close to polar head groups of the ethylhexyl chains, The base-catalyzed H-D exchange reaction between the AOT-(CH)-C-1 proton and solubilized D2O deuterium has also been investigated in this temperature range. Kinetic analysis, based on the time dependence of the H-1 NMR spectrum, has allowed evaluation of the thermodynamic parameters of the exchange reaction to be made. These show a marked difference between the two temperature ranges 323-343 and 343-353 K. In particular, it has been suggested, from the C-13 chemical shift data, that the local concentration of the OD- anions has a considerable influence on the H-D exchange reaction in the temperature range 323-353 K.